There have been studies that point to a clear association between finasteride usage and an increase in depression in those who use it. Why this occurs has been a matter of speculation, however some studies have elucidated the mechanism by which this occurs

Finasteride causes reductions in allopregnenolone, a potent, endogenous positive modulator of the GABA-A receptor, in very large doses in rodent studies.

5alpha-reductase, which finasteride inhibits, is a critical enzyme in the conversion of several steroids such as testosterone, progesterone, aldosterone and corticosterone in the brain. This enzyme converts testosterone to the most natural potent androgen DHT, and also it acts an important role in conversion of progesterone to dihhydroprogesterone (DHP). DHP is further converted to allopregnenolone (5alpha, 3alpha-tetrahydroprogesterone) by 3alpha-HSD. Allopregnanolone is a modulator of gamma amino butyric acid type A receptor (GABA-A), and increases chloride conductance. This neurosteroid has been found to exert anti-convulsant, anesthetic and anxiolytic effects. Moreover, change in the levels of allopregnanolone is found to be associated with depressive disorders.

The perceived dilemma for those using finasteride is that although finasteride may predispose to depression, the progression of MPB can also have severe depressive consequences as well.

You notice we said “perceived” dilemma. Fortunately there are other ways to lower serum dht (finasteride’s mechanism of action) and additionally reduce its binding to receptor sites. I personally discontinued the ¼ tablet of Proscar in 2004 I had been using for 12 years for health reasons with no negative consequence to my hair.

Considering my aggressive treatment regime this is not surprising.

Although I had no “apparent” issues with depression, my libido, which would you had asked me while on finasteride, I’d have insisted was fine, skyrocketed a few weeks after discontinuing Proscar.

This data on finasteride and depression provide yet another compelling reason not to use it. In a nutshell, finasteride is: only transiently effective at growing hair, has sexual side effects, increases estrogen, body fat, and often causes breast enlargement in men, and increases the incidence of depression. This would all be more tolerable if finasteride reliably stopped hair loss and regrew hair, but unfortunately, it doesn’t.

If you must use Propecia, you can likely offset this reductions in allopregnenolone and the resultant cognitive deficits and depressive symptoms by supplementing with Pregnenolone. Pregnenolone is metabolized sequentially to 5a-dihydroprogesterone and 3a,5a-. tetrahydroprogesterone (3a,5a-THP) or allopregnenolone. Based upon this data, it would be prudent for anyone currently using Propecia, Proscar, and/or Avodart to adjunctively use 50-100 mg of Pregnenolone a day. Your mood and cognitive functioning may well depend on it.